This invention relates to a moving unit that can be utilized as a transporting unit, care aid equipment, walking aid equipment, rehabilitation training equipment, an electric wheelchair or a wheel-moving robot.
(1) Varieties of moving units have been developed. For example, a forklift, a lifter or a handcart is well-known as a moving unit for transporting goods and a wheelchair is well-known as a moving unit for transporting a person.
However, all of passages where the moving unit moves are not flat and there might be a staircase or an obstacle on the passage. Then it is difficult for the moving unit having a wheel to move over a level difference whose height exceeds a radius of the wheel.
In order to make it possible for a moving unit having a wheel to move on a passage having a level difference, a level difference overcoming mechanism in which a multi-joint link or the like is incorporated has been developed so as to lift up a body portion of the moving unit.
However, the multi-joint link has a large number of components, which makes is difficult to downsize a body portion. Especially for a moving unit that transports a small package with two wheels driven it is preferable to incorporate the level difference overcoming mechanism into a body portion in a compact state.
The present claimed invention intends to realize a moving unit that is provided with a function which can serve as a role of a level difference overcoming mechanism and can be applied to other diversity of usages as well.
(2) Conventionally, in order to make it possible for a machine to make an up and down movement to go up or down a level difference such as a staircase, the machine is provided with a mechanism of the up and down movement which has previously been designed to make a specific movement in accordance with a shape of a level difference or the machine is loaded with a camera so as to recognize a level difference by an image processing.
However, for a case that the up and down mechanism has been designed in accordance with a shape of the level difference, a range of a level difference with which the up and down mechanism can deal is restricted and it becomes difficult to cope with a diversity of shapes of level differences, which leads to a problem such as that it does not function sufficiently and it is difficult to secure safety.
For a case of image processing, there is a problem that it requires a complicated and advanced signal processing and that accuracy in detecting the level difference is not high in spite of the complicated and advanced signal processing required.
(1) In order to solve the problem a moving unit of the present claimed invention comprises a wheel that supports a body portion in a condition that the body portion can be moved, a supporting member that is rotatably mounted at a position that does not interfere rotation of the wheel in a condition that can be driven and an arm that is mounted at a position shifted from a rotational center of the supporting member and that can move a distal end of the arm toward a direction away from the rotational center of the supporting member by being driven with the supporting member as a foothold, and is characterized by that the body portion can be lifted up together with the wheel by grounding the distal end of the arm when the moving unit is moved. It is especially preferable that the supporting member is mounted on the same axis as an axle of the wheel in order not to prevent rotation of the wheel.
With the above arrangement, it is possible to move a position at which the arm is supported by the supporting member within a movable range if the supporting member is rotated around the axis on which the supporting member is mounted. If the distal end of the arm whose supported position has been moved is driven by a supporting member so as to move toward a direction away from the axle, the body portion can be lifted up to a position where a level difference can be overcome by making use of reaction when the distal end of the arm touches a corresponding face every time the arm moves. Especially, in case that the supporting member is arranged to have the same axis as that of the axle of the wheel, the arm also rotates around the axle of the wheel. As a result, there is no need of considering interference among the supporting member, the arm and the axle of the wheel and it becomes possible to incorporate the arm and the supporting member around the axle in a compact state. It is a matter of course that the level difference overcoming mechanism can be arranged on a position a little shifted from the axle.
It is preferable that a driving system that drives the supporting member and a driving system that drives the arm are arranged so that each of the driving systems operates independently.
In accordance with the arrangement in which each of the arm and the supporting member is driven by a different driving system, it is possible to operate the supporting member and the arm independently, which makes it possible to operate the supporting member and the arm optimally based on a height of a level difference so as to minimize an up and down movement of the moving unit. As a result, jolt that is applied to a load or a nursed person (in case of a wheel chair) becomes small and force that is applied to the handle also becomes small. In addition, in case the moving unit is utilized as care aid equipment, it is possible to reduce a load for a cared person and a care person as well.
Especially, if the arm is arranged to be grounded near a position where the wheel is grounded, it becomes possible for the center of gravity to move less when the load is transferred from the wheel to the arm, thereby to make a movement of transferring the load smooth and effectively to prevent unstable condition due to force occurring in a moment of transferring the gravity as well.
As a result of this, since the moving unit of the present claimed invention has a pair of parallel wheels as a driving wheel and the body portion is supported by an operator through the handle while moving a passage having a level difference, it can be extremely preferable to reduce a load for an operator.
As a concrete arrangement of the arm it is preferable that the arm is in a vertical posture and at least a distal end of the arm is accommodated within a diameter of the wheel when a position where the arm is supported by the supporting member locates vertically above the axle of the wheel and that the arm moves toward a direction to project the distal end of the arm out of the diameter of the wheel when the position where the arm is supported by the supporting member moves away from the above position.
In order to make it possible to rotate a position at which the arm is supported at 360 degrees without interfering a movement of the wheel when the arm and the supporting member rotates together with the wheel it is preferable that each of the arm and the supporting member is in a shape that can be accommodated within a diameter of the wheel.
It is a matter of course that the moving unit can be utilized as objects or usages other than overcoming a level difference by making use of the above-mentioned fundamental movement.
(2) In addition, a moving unit of the present claimed invention comprises a wheel that supports a body portion in a condition that the body portion can be moved, a supporting member that is mounted at a position that does not interfere rotation of the wheel in a condition that can be rotatably driven and an arm that is mounted at a position shifted from an axis of the supporting member and that can move a distal end of the arm toward a direction away from the axis of the supporting member by being driven with the supporting member as a foothold and is characterized by that a detecting means is provided at a side where the arm is grounded so as to measure a shape of level difference by moving the detecting means with an operation of the arm in the level difference.
With this arrangement, a separately provided detecting means is not required since the arm that is used for an up and down movement can be utilized as the detecting means and an advanced processing such as an image processing is not required as well, resulting in providing a simple and secure function of overcoming a level difference. In addition, since this moving unit makes use of a continuous movement of the arm that makes an up and down movement in order to detect a level difference, it is possible to detect the level difference effectively. Further, it only requires the arm be controlled in accordance with the detected level difference, which makes it possible to deal with a diversity of level difference simply and securely.
Especially it is preferable that the supporting member and the arm are arranged to gather around a center between the facing wheels. With this arrangement, it is possible to provide the moving unit as far as there are at least a set of a supporting member and an arm, thereby to improve safety for a person who is around the wheel.
It is preferable that a grounding portion of the arm is ark-shaped and so arranged to roll over the ground. With this arrangement, since a position where the body portion is supported moves from the wheels to the level difference through the arm smoothly, force applied to the handle and fluctuation of force applied can be made small as well. Further, since rotation of the arm propels the body portion to move forward (backward), force that is to be applied forward (backward) by the operator will be made small when the moving unit moves in a passage with a level difference, thereby to lessen a load for the operator.